The present invention relates to the development of a frost resistant high yielding lemongrass plant xe2x80x98Chirharitxe2x80x99 through extensive selection for frost resistant variants in open pollinated seed progeny of the familiar variety xe2x80x98Cauveryxe2x80x99 under hostile environment of chilling winter of the foot hill areas. The selections were made under high stringency of sustaining normal growth behavior under natural frosting. The variety xe2x80x98Chirharitxe2x80x99 is capable of being propagated vegetatively by tillers, its all morpho-physiological plant attributes are firmly fixed so as to give a guarantee for sustained yield advancement.
Lemongrass oil, a major source of citral (Vit-A precursor), is one of the top 10 essential oils produced in the world. India is a major producer of this oil. Although resorting to different plant breeding approaches, especially population improvement via the scheme of phenotypic recurrent selections, has resulted in the development of a couple of high yielding varieties in the past, no efforts have yet been made in this crop for sustainable advancement in productivity. Attempts in ensuring genetic rectification for its productivity-sustainability is needed to be directed to the following as yet untouched aspects given below:
1. Frost resistance in lemongrass: Lemongrass is long known to be much prone to frost injuries often marked by the dark purple pigmentation of the leaves, especially when this crop is grown in foothill areas (Tarai). Until now, not even a single high yielding variety is available which would successfully withstand prolonged frost and sustain its high productivity even under hostile environmental situations of frost in winter. Genetic improvement for frost tolerance would help this crop remain healthy in all seasons and thereby, would lead to its capability in giving an additional economic harvest in even winter season.
2. Stay-green lemongrass: The productive life of this multicut perennial grass is normally five years. Its leaf yield is maximum during its second and third years and starts declining thereafter. Such decline in leaf yield is directly associated with poor tiller regeneration and is invariably accompanied by disproportionate increase in crop stubble-debris; it is envisaged that a stay-green mutant having no unwanted stubble would merit a high price in lemongrass.
Keeping these two aspects of the limitations of the plant in view, planned efforts were made at this Institute""s (CIMAP""s) headquarters at Lucknow and its field station in Pantnagar to explore the possibility of obtaining a frost resistant genotype with high yield potential and stay-green habit within the otherwise high yielding variety through extensive clonal selections in its open pollinated seed progeny.
The main objects of the invention are to develop a novel lemongrass plant called xe2x80x98Chirharitxe2x80x99 which is highly resistant to frost and capable of adapting to favorable and unfavorable conditions.
Another object of the invention is to develop a novel lemongrass plant capable of producing large number of tillers even in winter.
Yet another object is to develop novel lemongrass plant capable of high yield of oil in winter.
Still another object is to develop a novel lemongrass plant generating high biomass and oil yields throughout the year.
Another object is to develop a novel chromosomal mutant of lemongrass variety xe2x80x98Cauveryxe2x80x99 and having distinct morphology.
The invention relates to a development of a novel high yielding and stable plant of Cymbopogon flexuosus, called xe2x80x98Chirharitxe2x80x99 having the following combination of plant traits:
(a) Said plant is a tetraploid variant (chromosomal mutant) of the normal diploid lemongrass variety xe2x80x98Cauveryxe2x80x99 and having distinct morphology.
(b) Being highly resistant to frost and adapted to both favorable as well as unfavorable environments of regular frosting situations,
(c) Producing high biomass,
(d) Having high yield of essential oil,
(e) Capable of growing in all seasons and producing the same yield,
(f) Producing essential oil with high citral pungency conforming to the standard citral concentration much useful in pharmaceutical and perfumery industries, and
(g) Producing essential oil containing about 80% or more of citral.
The plant was selected and isolated through large scale clonal selection in open pollinated seed progenies of xe2x80x98Cauveryxe2x80x99 for any variability through natural out-crossings. The plant is a spontaneous tetraploid (2n=4x=40) against the existing varieties which are all diploids with chromosome number 2n=2x=20. The plant was asexually produced a Pantnagar, Lucknow, India, at the Central Institute of Medicinal and Aromatic Plants. Field trials were carried out in a field station named Pantnagar, which is a small area near the city of Lucknow.
The invention is described in detail herein below. The description is provided merely to illustrate certain aspects of the novel plant and should not be construed as limitation on the inventive concept.